The ongoing research program on DNA repair and meiosis in yeast involves extensive analysis of DNA changes during meiosis and after treatment with mutagens. The primary means of assessing changes is through the use of sucrose gradient analysis of large molecular weight chromosomal DNA. Because of the extensive data and calculations required, we are developing an interactive computer program to store and analyze data directly from the scintillation counter with several options for mode of analysis and means for comparison by utilizing the NIEHS PDP11 computer, the PROPHET system, and RS1.